Likelihood fit of tt signal + QCD background to data.


In this work, a measurement of the top quark-antiquark pair (tt ̄) production cross section is presented, using data from pp collisions collected by the CMS detector in 2016 at CERN, with a centre-of-mass energy of 13 TeV, and corresponding to an integrated luminosity of 37 fb^-1. The analysis has been performed in the all-jets boosted channel, characterized by the presence of two wide jets, stemming from the boost of the particles originating from the hadronic decay into a W boson and a b quark of the top quark. Candidate events have been selected using a multijet trigger, specific kinematic and b-tagging requests, and a multivariate analysis in order to enhance the signal from the large background. Then a likelihood fit has been performed which yields a cross section of 554 ± 12 (stat) ± 283 (sys) pb, where some of the main sources of systematic uncertainty have been considered. This measurement is consistent with what expected from theoretical calculations.